This invention relates to surgical instruments incorporating scissors and to surgical scissors, and more particularly to surgical scissors having electrocautery electrodes disposed adjacent tissue-cutting blades for selective cauterization and shearing of tissue.
Endoscopic surgery commonly requires manual manipulation of surgical instruments that are introduced into a surgical site within a patient through elongated cannulas containing one or more interior lumens of slender cross section. Endoscopic surgery to harvest a sapbenous vein usually involves an elongated cannula that is advanced along the course of the vein from an initial incision to form an anatomical space about the vein as connective tissue is dissected away from the vein.
Lateral branch vessels of the saphenous vein can be conveniently isolated and ligated within the anatomical space under endoscopic visualization using surgical scissors that can be positioned and manipulated through the elongated cannula. Such surgical procedures are commonly employed in the preparation of the saphenous vein for removal from within the anatomical space for use, for example, as a shunting or graft vessel in coronary bypass surgery.
Surgical scissors that are used to transect vessels within the confines of limited anatomical space formed along the course of the saphenous vein commonly incorporate electrodes on or near the tissue-shearing blades. Scissors of this type are suitable for monopolar or bipolar electrocauterization of tissue prior to transection of, for example, lateral side branches of the saphenous vein to be harvested. However, placement of the electrodes in relation to the tissue-shearing edges of the blades may inhibit proper operation of the blades to shear tissue and may inhibit thorough electrocauterization of a side branch vessel as the blades close during transection of the vessel.
In accordance with the present invention, surgical scissors include scissor blades mounted at the distal end of a slender body for manual manipulation under control of a lever mounted at the proximal end of the slender body. The scissor blades support electrodes that are positioned to supply electrical energy from external sources to cauterize tissue prior to shearing the cauterized tissue at a remote surgical site in a patient. The electrodes of various configurations are spaced from, and are electrically isolated from, the tissue-cutting blades (or at least from one such blade) in order to optimize both the ability to shear tissue as well as the ability to localize the electrocauterization of the tissue to be sheared within a wide angle of alignment of tissue relative to the blade.
Surgical scissors in accordance with the present invention may be incorporated into and form an integral part of more comprehensive surgical apparatus, for example, as illustrated and described with reference to FIGS. 8 and 9 of pending application Ser. No. 10/054,477, entitled xe2x80x9cVessel Harvesting Apparatus and Methodxe2x80x9d, filed on Jan. 18, 2002 by M. Stewart et al.